minutes. ser sister alone for the first time. >> i hope they find a cure for alzheimer's. marion visited vivian almost daily, thanks to an outpouring of donations that allowed her to stay in the city. >> people would e-mail with money to offer help and volunteer to donate. services are costly when you are elderly and you need care. >> caretakers say vivian finally passed away, peacefully in her sleep. >> the brown twins were so impeccable in their identicalness, even people who know them for decades say there isn't a story, a conversation or even an outfit that was just one of them. >> could you tell them apart? >> no, i couldn't tell them apart. honestly, i could not tell them apart. there was no way to tell them apart. as a matter of fact,, you would not want to tell them apart. >> former mayor, willie brown, said the twins embodied the uniqueness that represents san francisco. >> their passage means one-half of that theme is now gone.